As a small boy, Derek was at home alone. That is, his mom and dad were out and only the nanny (who also was the housekeepster) was there. He has some kind of mental affliction which makes him behave unlike other people. He constantly moves his body. and is the incarnation of politeness (though Tourette hits strongly...damned prick!... once and a while, like tic).

There was a piano in the house. Derek, on that lonely night, wanted to give it a go. What followed popped out the eyes and ears of the nanny. He played "Cockles and Mussels" without ever practiced it! How is that possible? By his approach to the piano?